Direction of oil flow: A - valve is off; B - valve is on
The system is driven by engine oil pressure in the engine lubrication system and is controlled by the engine control unit (ECU) using electromagnetic valves.
The system's actuators are two hydraulically controlled phase regulators installed in the camshaft pulleys. Oil enters the phase regulator from the engine lubrication system through the phase change valve. It can be supplied through one of two channels, while it returns to the engine oil sump through the free channel. Depending on the direction of oil movement through the phase regulator, the angle of rotation of the shaft relative to its pulley is set and the valve timing is shifted. The flow of oil into the phase regulator is changed according to the commands of the electronic control unit. Depending on the engine operating modes, the ECU turns the valve on or off, and the valve locking mechanism connects the oil channels of the system in a certain way.
After the engine stops, the springs return the phase regulators to their original position. If the valve timing change valve or its electrical circuit is faulty, the normal operation of the system will be disrupted, fuel consumption will increase, and engine power will decrease. At idle and in transient modes, the engine may operate unstably. The engine management system malfunction indicator light may also come on. To identify the causes of the malfunction, it is necessary to diagnose the engine management system and check the phase change valve. The faulty valve must be replaced.
Replacement. The work is shown using the example of replacing the exhaust phase change valve, the intake phase change valve is replaced in a similar way.
To complete the job you will need a new valve gasket, a multimeter and two pieces of wire.
1. We prepare the car for maintenance and repair.
2. Move the locking mechanism.
3. Press the lock...
...and disconnect the wiring harness from the valve that changes the exhaust phase.
4. Inspect the connector and make sure there is no corrosion or damage. If necessary, we treat it with a special agent for cleaning electrical contacts and clean the contacts from oxides.
5. Connect the positive probe of the multimeter, switched on in voltage measurement mode, to contact 2 of the wiring harness block, connect the negative probe to the ground and turn on the ignition. The multimeter should show the battery voltage. If there is no voltage, then check the electrical circuit to fuse Ef47 in the engine compartment fuse and relay box.
Note. You can check the serviceability of the electromagnetic valve by measuring the resistance at its terminals, which should be within 7-20 Ohms. When voltage is applied from the battery to the valve terminals, it should operate with a characteristic click.
6. Using a TORX E8 socket wrench, unscrew the mounting bolt and remove the valve. The connection is sealed with a rubber ring, which must be replaced when reinstalled.
7. Install the valve with a new sealing ring in the reverse order. Before installation, apply a thin layer of motor oil to the sealing ring. Tighten the valve mounting bolt to a torque of 7-9 Nm.
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